Retraction apparatus and method of use

ABSTRACT

A retraction apparatus and method are disclosed that provide optimized access to a surgical site. In one form, a retraction frame has a retraction opening with two sets of blades operating therein. The blades are used to sequentially retract the tissue from about an incision. The sequential retraction of the blades generates only narrow gaps between the blades so that tissue and blood encroachment during the surgical procedure are minimized.

FIELD OF THE INVENTION

The invention relates generally to a retractor and method for providingaccess to a surgical site and, more particularly, a retractor and methodfor retracting tissue during a surgical procedure.

BACKGROUND OF THE INVENTION

While incisions are required during surgical procedures to gain accessto the surgical site, such incisions can cause damage, injury, andtrauma to the patient's body. To avoid causing unnecessary damage, it ispreferable to make the incisions as small as possible, while retaining aclear view of the surgical site. Retractors are used to maximize theviewing range of incisions, thereby allowing the surgeon to minimizedamage.

In addition, retractors are used to keep the incision open and provide aclear view of the operating site during the procedure. Retractors can beused to relocate various types of tissue, nerves, bone, cartilage, andligaments. Such repositioning is often accomplished by employing tissueengaging members or blades that reposition and retain the tissue andother bodily substances in the adjusted position thereby providingclearance to the surgical site.

A significant problem with retractors currently used during surgicalprocedures, is that after the blades are moved from the unretractedposition to the retracted position, the blades are spaced significantlyapart. The space between the retractor blades allows tissue, and bloodto encroach upon the surgical site. The gaps can become increasinglyproblematic throughout the procedure.

Accordingly, there is a need for an access retractor that repositionstissue and blood from a surgical site and minimizes tissue encroachmentthroughout the duration of the surgical procedure.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, accessretraction apparatus and methods are disclosed that provide optimizedaccess to a surgical site through an incision during a surgicalprocedure. To this end, the apparatus and methods utilize tissueengagement members, such as in the form of retractor blades. Theretractor blades are operable to pull tissue about the incision apartwhile substantially minimizing tissue and blood encroachment into thesurgical site during surgical procedures. The preferred retractorincludes a frame or body having a retraction opening in which theretractor blades are operable to provide optimized access to thesurgical site by keeping tissue encroachment beyond the retracted bladesto a minimum. Sets of opposing blades are provided, including a sethaving a narrow width and a set having a comparatively wide width.Operating mechanisms for the blades are configured to allow forsequential retraction of the sets of blades which, in turn, allow forgaps between the blades to be minimized in size.

In a preferred form, the narrow width blade set is initially retractedin a first direction. The wide width blade set can then be inserted intothe enlarged opening and retracted to further enlarge the opening in asecond direction transverse, and preferably perpendicular, to the firstdirection in order to retract the tissue to form an oblong openingsurrounded by the blades. The use of two different blade widths and thesequential use of those blades permits the gaps between adjacent bladesto be minimized to reduce encroachment of tissue through the gaps.

Before the access retraction apparatus is employed, an incision is madeinto the patient's body where access for surgical instruments through anincision into a patient's body is desired. After making the incision,the access retractor may be utilized with the two narrower blades intheir fully extended, unretracted position, closely adjacent oneanother. By first using the narrower blade set for retraction prior tothe wider blades, the size of the incisions can be kept to a minimum.Alternatively, a harpoon dilator or number of cannulated tools can beused to stretch the skin, after which the blades of one of the bladesets of the access retractor are inserted over the dilation tool. Inthis regard, the blades can be retracted to an intermediate positionbetween fully retracted and fully extended relative to the retractionopening so that the blades are sufficiently spaced to allow them to bepositioned in a close fit around the dilation tool.

Each of the blades is preferably removably attached to a slidermechanism to allow for shifting of the blades to different positions.The set of narrower blades, which retract first, preferably have aratcheting slider mechanism that provides retraction over smallincrements. This provides numerous closely spaced, predeterminedretraction positions for the narrow blades. Subsequently, the wideblades are retracted. The wide blades can be selected from a pluralityof different widths. In one aspect, the wide blades have only twopositions, retracted and extended. In another aspect, the wide bladesalso use a ratcheting slider mechanism that provides retraction oversmall increments. The width of the wide blades used is limited by howfar the narrower blades were retracted in the first or initial stage ofretraction. Substantially matching the width of the wide blades to thedistance traveled by the narrow blades during the first retraction stageensures that minimal space will be available between the blades fortissue encroachment. In addition to allowing for different sizes ofblades to be interchanged, and in particular for the blades of the wideblade set used with the retractor, the detachable connections alsoenable the blades and slider mechanisms to more easily be cleaned andsanitized.

To move the blades between the different retraction positions, aspreading instrument can be employed. The spreading instrument mayinclude a pair of connecting arms which guide the retraction movementbetween the frame and the blade. When retracting the blades, theconnecting arms are rigidly connected to attachment structure such as inthe form of pegs, cylinders, or holes on the frame and sliders. Afterthe blades have been moved to the retracted position, the slidermechanism locks into place and the spreading instrument can be removed.The spreading instrument may comprise a lamina spreader that is used tosimultaneously retract opposing blades.

Since the wide blades come in varying widths and the narrow blades canbe retracted to a large number of different positions, the accessretractor can be used for many different surgical procedures and fordifferent patients. The primary use for the access retractor illustratedherein will be for use during a surgical procedure requiring access tothe lumbar spinal region.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of an accessretractor in accordance with the present invention shown with first andsecond sets of blades in the fully retracted position;

FIG. 2 is a bottom plan view of the access retractor shown with thefirst set of blades in an intermediate position for use with a tubulardilator tool;

FIG. 3. is a bottom plan view of the access retractor shown with thefirst set of blades in the full retracted position, and the second setof blades removed from the retractor;

FIG. 4 is a bottom plan view of the access retractor shown with thefirst set of blades in the retracted position and with the second set ofblades attached to the retractor in the first extended position;

FIG. 5 is a bottom plan view of the access retractor showing the firstand second sets of blades in the full retracted positions and a pair ofconnecting arms attached to a frame of the retractor and one of the armsbeing attached to a slider mechanism for a corresponding one of theblades of the first blade set;

FIG. 6 is a perspective view of the access retractor similar to FIG. 1and showing the attached connecting arms as in FIG. 5;

FIG. 7 is a bottom plan view of the access retractor showing the firstand second sets of blades in the full retracted positions and anotherpair of connecting arms attached to the retractor frame with each armattached to a slider mechanism for opposite blades of the second bladeset;

FIG. 8 is a side elevational view of a spreading instrument showing ascissor-arm arrangement including a pair of pivotal operating arms andlinkages for actuator arms that are to be attached to the connectingarms;

FIG. 9 is a perspective view of the spreading instrument showing aspring loaded ratchet mechanism for the operating arms;

FIG. 10 is a perspective view of the spreading instrument showing theoperating arms moved toward each other with the linkages being operableto shift the actuator arms away from each other;

FIG. 11 is a side elevational view of the spreading instrument similarto FIG. 10 showing the actuator arms shifted apart and in parallelorientation relative to each other.

FIG. 12 is a cross-sectional view of the slider mechanism of FIG. 5 withthe blade removed;

FIG. 13 is a cross-sectional view taken along line 13-13 of FIG. 5showing a slider mechanism for blades of the second blade set includinga slider carrying a detent for forming the detachable connection withthe blade and a position selector for releasably fixing the blade indifferent positions;

FIG. 14 is a cross-sectional view taken along line 14-14 of FIG. 3showing a ratchet slider mechanism for blades of the first blade setincluding a slider carrying a detent for forming the detachableconnection with the blade and a position selector for releasably fixingthe blade in different positions;

FIG. 15 is a top perspective view of a second embodiment of an accessretractor in accordance with the present invention shown with the firstset of blades attached to the slider mechanisms of the major axis in anextended position and the slider mechanisms of the minor axis in anintermediate position;

FIG. 16 is a top plan view of the access retractor of FIG. 15;

FIG. 17 is a cross-sectional view of the access retractor taken alongline 17-17 of FIG. 16;

FIG. 18 is an exploded perspective view of a plunger assembly of theaccess retractor of FIG. 15;

FIG. 19 is a top plan view of the access retractor of FIG. 15 with theslider mechanisms associated with the first set of blades in a fullyretracted position and the second set of blades attached to the slidermechanisms of the minor axis in an extended position;

FIG. 20 is a top plan view of the access retractor of FIG. 15 with theslider mechanisms associated with the first set of blades in a fullyretracted position and the slider mechanisms associated with the secondset of blades in a fully retracted position;

FIG. 21 is a perspective view of a slider mechanism of FIG. 15 for usewith the first set of blades;

FIG. 22 is a top plan view of the slider mechanism of FIG. 21;

FIG. 23 is a bottom plan view of the slider mechanism of FIG. 21;

FIG. 24 is a perspective view of a slider mechanism of FIG. 15 for usewith the second set of blades;

FIG. 25 is a top plan view of the slider mechanism of FIG. 24;

FIG. 26 is a bottom plan view of the slider mechanism of FIG. 24;

FIG. 27 is a rear perspective view of one of the first set of blades ofFIG. 15;

FIG. 28 is a rear elevation view of the blade of FIG. 27;

FIG. 29 is a front elevation view of the blade of FIG. 27;

FIG. 30 is a rear perspective view of one of the second set of blades ofFIG. 19;

FIG. 31 is a rear elevation view of the blade of FIG. 30;

FIG. 32 is a front elevation view of the blade of FIG. 30; and

FIG. 33 is a perspective view of a spreading instrument that can be usedto retract opposing blades.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Access retractors are illustrated in FIGS. 1-32 for use in enlarging asurgical incision for a surgical procedure, and in particular forstretching the tissue surrounding the incision. The access retractorsuse multiple stages of retraction of a plurality of tissue engagingmembers in order to minimize gaps between the tissue engaging members toadvantageously reduce the encroachment of tissue, fluid and other matterthrough the gaps. More specifically, a first, narrow set of tissueengaging members are inserted into the incision and moved from anextended position toward a retracted position using the access retractorin order to stretch the incision to an intermediate size opening. Next,a second, wider set of tissue engaging members are inserted into theintermediate size opening and moved from an extended position toward aretracted position to stretch the intermediate size opening to a finalsize opening. The sequential use of two different sets of tissueengaging members, each having a different width, can result in an oblongopening bounded by the tissue engaging members having minimal gapsbetween adjacent ones of the tissue engaging members, in particular ascompared to using equal width tissue engaging members.

In FIG. 1, a first embodiment of an access retractor generallydesignated 10 is depicted in the fully retracted or open positionthereof. The retractor 10 includes a frame or body 12 having a largeretraction opening 14 centrally located for viewing the surgical site.Inside the viewing window 14 are located a number of tissue engagingmembers, such as in the form of retraction blades 16, 18, 20, and 22. Tokeep gaps between adjacent, retracted blades to a minimum, it ispreferred to undertake the retraction procedure in different stages sothat retraction of an incision occurs sequentially with the preferredretractor 10 described herein. In the illustrated and preferred form, itis the narrower blades 16 and 18 disposed opposite from each otheracross the retraction opening 14 that are retracted during the first orinitial stage of the retraction procedure and the wider blades 20 and 22disposed opposite from each other across the retraction opening 14 thatare retracted during the second or final stage of the retractionprocedure. The sequential use of narrow blades 16, 18 and wide blades20, 22 can advantageously result in an enlarged opening substantiallysurrounded by the blades 16, 18, 20 and 22, with reduced gaps betweenadjacent ones of the blades 16, 18, 20 and 22 to minimize encroachmentof tissue and other matter through the gaps.

More generally, the first retraction stage involves retracting theblades 16 and 18 in a direction 24 that is transverse to the direction26 in which the blades 20 and 22 are retracted in the second stage. Inthis manner, the blades 20 and 22 can be sized to be larger than theblades 16 and 18 since these blades 16 and 18 have already been used toexpand the size of the incision into which they extend to form anopening 30 that generally has an enlarged size in the direction 24 ofretraction. Referring to FIG. 3, the opening 30 may take on a generallyrectangular configuration with the width of the blades 16 and 18generally defining the size of the opposite short sides 32 and 34 of therectangular opening 30. The position that the narrower blades 16 and 18are retracted to will define the size of the opposite long sides 36 and38 of the rectangular opening 30. In other words, the distance thenarrow blades 16 and 18 are spaced from each other across therectangular incision opening 30 after the initial stage of theretraction procedure will generally define the length of the long sidesof the rectangular opening 30. The size of the rectangular sides limitsthe width of the blades 20 and 22 that can be fit within the opening 30for undertaking the next stage of the retraction procedure.Nevertheless, it can be seen that the width size of those blades 20 and22 in the longitudinal retraction direction 26 of blades 20 and 22 aregenerally aligned with the orientation of the long sides 36, 38 of theopening 30 and can be larger than the blades 16 and 18.

Thus, the blades can be provided in sets so that there is a narrow bladeset including the blades 16 and 18 and a wider blade set including theblades 20 and 22. Because the blades 16 and 18 can be retracted to alarge number of different positions as will be described in more detailhereinafter, the blades 20 and 22 can be provided in a number ofdifferently sized wide blade sets for fitting in the opening 30depending on its size as determined by how far the blades 16 and 18 areretracted apart from each other. Accordingly, while the narrow blade setcan include a single width size of narrow blades 16 and 18, the wideblade set preferably includes several different width sizes of wideblades 20 and 22. Manifestly, the retractor 10 herein can be used withblades and sets of blades in a wide variety of numbers and sizes, notlimited by the preferred arrangement described therein.

The narrow retraction blades 16 and 18 are attached to slider mechanisms40 and 42 that shift the blades between an intermediate position (FIG.2) to the retracted position (FIG. 3). The access retractor 10 can beused immediately after the incision is made into the body. This requiresthat the slider mechanisms 40 and 42 be in the completely extended orunretracted position. Alternatively, a generally tubular dilation toolcan be used to stretch the skin about the incisions before employing theretractor. In that situation, the slider mechanisms 40 and 42 areretracted to a predetermined, intermediate position as indicated by the“tube” setting on scale 44 for the slider mechanisms 40, 42 of thenarrow blades. In this position, the blades are sufficiently spacedapart so that the arcuate facing surfaces 46 and 48 of the oppositeblades can slide around the tubular tool. FIG. 2 illustrates the tubeconfiguration of the tool.

The narrow blades 16 and 18 each have an upper attachment end 50 thatattaches the blades 16, 18 to the retractor, and specifically the slidermechanisms mounted thereto, and a lower insertion end 52 that extendsinto the incision. After the retraction frame 12 and sliders 40, 42 havebeen positioned over the incision, the insertion ends 52 of the narrowblades 16 and 18 can be slid into the incision and the attachment ends50 can be attached to the sliders 40 and 42.

Each of the blades is attached to the slider mechanisms by a dovetailconnection 54, 56, 58, and 60. More specifically, narrow blades 16 and18 have dovetail recesses 62, and the sliders 40 and 42 have dovetailprojections 64 sized for a sliding fit in the corresponding recesses 62.As will be discussed further below, the dovetail connections 54, 56, 58and 60 allows for the removal of the blades.

In the preferred form, the sliders 40 and 42 are ratcheting slidersallowing for small discrete movements of the narrow blades 16 and 18.Preferably, the narrow sliders 40 and 42 can be shifted to severaldifferent predetermined positions from “0” at the fully extendedposition in the retractor opening 14 with the blades 16 and 18 at theclosest position to each other to “65 mm” at the fully retractedposition in the retractor opening 14 with the blades 16 and 18 at theirfurthest position spaced apart from each other. More specifically, theblades have a full extended position at “0” for use where no dilationtool is employed prior to use of the retractor. If a dilation tool ispresent in the incision, then the “TUBE” setting can be used to spacethe blades 16 and 18 from each other across the opening 14 so that therespective arcuate, inner surfaces 46, 48 thereof can slide down alongthe outer cylindrical surface as defined by the circle of FIG. 2 of thetool in close fit therewith. This “TUBE” setting is for a specificdiameter dilation tool. Manifestly, this setting can be implemented byproviding at different positions along the scale 44 depending on thetool diameter. Regardless of the starting position, the sliders 40, 42and associated blades 16, 18 can be retracted from this position topositions where the blades 16, 18 are spaced 40 mm from each otheracross the opening 14 by 5 mm increments up to the fully retractedposition where the blades 16, 18 are spaced 65 mm from each other acrossthe opening 14. As shown in FIG. 3, the narrow blades, 16 and 18 havebeen retracted to the 60 mm spaced apart position.

After this initial stage of the retraction procedure, the sliders 66 and68 for the respective wide blades 20 and 22 are shifted to theirextended positions in the retractor opening, and the appropriately sizedwide blades 20 and 22 are selected and attached thereto to fit into therectangular opening 30 formed by the retracted narrow blades 16 and 18,as described earlier. Preferably, the narrow slides can be shifted atincrements of 2.5 mm, as can be seen by the scale 44 on retractor 10shown in FIGS. 1-3 and 5-7. Other incremental movements, such as 3.25mm, are contemplated.

Similar to the narrow blades 16 and 18, the wide blades 20 and 22 areattached to the sliders 66 and 68 by a pair of dovetail connections 58and 60. Before the wide blades 20, 22 are attached the blade length mustbe chosen, as mentioned above. The wide blades can be provided in anynumber of sizes. By way of example, three sizes of wide blades can beprovided. A wide blade with a width of 32 mm is used for a narrow bladeretraction between 40 and 49 mm. A wide blade width of 42 mm is used fora narrow blade retraction between 50 and 59 mm. Finally, a wide bladewidth of 52 mm is used for a narrow blade retraction between 60 and 69mm.

As mentioned, the wide blades 20 and 22 may be provided with only twopositions via their respective slide mechanisms 66 and 68, an extendedposition and a retracted position in the retractor opening. A springloaded plunger assembly 70 is carried with each of the sliders 66, 68. Acoil spring 72 is mounted in a downwardly opening pocket 74 of a fixedsleeve member 76 of the plunger assembly 70 through which a plungermember 78 extends. The fixed member 76 is fixed to the slider 66, or 68toward its lower end. The spring 72 biases the distal end 80 of theplunger member 78 of the plunger assembly 70 out of the pocket 74 intoone of the two openings 82 and 84 which are linearly aligned in theretraction direction 26 along which the sliders are shifted. To shiftthe slider, a surgeon simply pulls on disc handle 86 connected at theproximate end of the plunger member 78 to lift the distal end 80 out ofthe opening 82 or 84 aligned therewith and into the pocket 74 so thatthe slider 66, 68 can then be shifted until the plunger end 80 isaligned with the other opening 82 or 84. The bias force provided by thespring 72 causes the end 80 to snap into the aligned opening 82 or 84for releasably locking the slider in the desired position. The twoopenings 82 and 84 correspond to the extended position and the retractedposition of the wide blades 20 and 22. After the initial stage narrowblade retraction procedure, the wide blade sliders 66 and 68 are shiftedto the extended position. The wide blades 20 and 22 are then slid downonto the sliders 66 and 68, respectively, for being attached thereto viathe dovetail connections 58 and 60 therebetween, as shown in FIG. 4.

Sliding the wide blades 20 and 22 down along the dovetail projections 64inserts the blades 20 and 22 into the rectangular opening 30 of theincision. The blades 20 and 22 and associated sliders 66 and 68 have areleasable connection 90 therebetween that is operable when the blades20 and 22 slide down to a predetermined position relative to the sliders66 and 68. The releasable connection 90 is shown best in FIGS. 12 and 13and will be described in more detail hereinafter.

With the blades 20 and 22 inserted into the rectangular incision opening30 and connected to their sliders 66, 68 as described above, the secondstage of the retraction procedure is then undertaken. In this stage, theblades 20 and 22 are retracted in a direction that is transverse to thedirection of retraction of the blades 16 and 18 in the initial stage ofthe retraction procedure. More specifically, the blades 20 and 22 arepreferably retracted in a lateral direction 26 that is perpendicular tothe longitudinal direction of retraction of the narrow blades 16 and 18for increasing the size of the incision opening in this direction. Thisincreases the size of the initial rectangular incision opening 30generated by the narrow blades to a larger width size rectangularopening 92, as shown in FIGS. 5-7. It can be seen that because of thesequential or staggered retraction procedures with the retractor 10described herein to create the initial or rectangular incision opening92 allowing for use of the wide blades 20 and 22, spaces or gaps 94between the adjacent blades 16, 18, 20 and 22 are relatively small oncethe final size of the incision opening 92 is created after bothretraction stages. In this manner, spaces for the encroachment of tissueinto the area of the opening that could otherwise obstruct or impede theuse of surgical instruments or proper surgical techniques is kept to aminimum. The openings 82 and 84 for receiving the plunger end 80 arealso illustrated in FIG. 4.

Each of the sliders 40, 42, 66, and 68 connects to a connection arm 96or 98 during retraction operations by retraction tool 100. Theconnecting arm 96 is the shorter arm used during the narrow bladeretraction operation. One of the longer connecting arms 98 is usedduring the narrow blade retraction operations while two long arms 98 areused during the second stage, wide plate retraction procedure. As shownin FIGS. 5 and 6, when either one of the narrow blade slides 40 or 42 ismoved, one short connecting arm 96 and one long connecting arm 98 areused so that each of the narrow blades 16 and 18 undergoes retractionindependent of the other. However, it is contemplated that both of thenarrow blades 16 and 18 can be retracted simultaneously as well. Asshown in FIG. 7, when shifting the wide blades 20 and 22 in the secondstage, two of the long connecting arms 98 are utilized.

The long connecting arms 98 used to retract the wide blades 20, 22 andslides 66, 68 each generally have an S-shaped configuration and are amirror image of each other, as can be seen in FIG. 7. The arms 98 have ayoke-shaped end 102 including spaced apart prongs 104 that can be fitabout the plunger assembly 70 below the disc handle 86 thereof. At theother end 108, the connecting arms 96 and 98 attach to the spreadinginstrument or tool 100 that shifts the blades and sliders.

FIGS. 5 and 6 illustrate the connecting arms 96 and 98 attached to theretractor 10 to move the narrow blades 16 and 18 during the initialstage of the retraction procedure. One end 110 of the short connectingarm 96 has a depending peg 112 that mates with an aperture 114 in theframe 12. In addition, the long connecting arm 98 connects to a largeslider pin 116 projecting upwardly from the narrow blade sliders 40, 42.This large slider pin 116 is securely gripped by a pair of prongs 104 atthe yoke end 102 of the arm 98.

FIG. 7 illustrates the wider blades 20 and 22 having been shifted to theretracted position with two of the long connecting arms 98 secured tothe respective plunger assemblies 70. After the prongs 104 of theconnecting arms 98 are placed on either side of the plunger assembly 70,the disc handle 86 is pulled up as force is applied to the spreadinginstrument 100, as described hereinafter, which allows the sliders 66,68 to be shifted to the retracted position.

As illustrated in FIGS. 6 and 7, opposite the ends 102 and 110 of theconnecting arms 96 and 98 are reduced ends 118 and 120 having agenerally square configuration with rounded edges and corners thatrigidly connect to the spreading instrument 100. The square ends 118 and120 are each provided with a small spring loaded detent projection toconnect the spreading instrument 100 and the connecting arms 96, 98.

FIGS. 8 and 9 illustrate the spreading tool 100 that attaches to theconnecting arms 96 and 98 during the retraction operations. Thespreading tool has a pair of pivotal operating arms or handles 124 and126. When the handles 124, 126 are squeezed, toward each other acorresponding pair of actuator arms move apart from each other stayingin parallel orientation via pivotal and slide bar linkages 128interconnecting the handle arms 124, 126 and actuator arms 130, 132.FIGS. 10 and 11 show the spreading instrument 100 after the spreadingoperation. Free ends 134 and 136 of the actuator arms 130, 132 havesmall, open-ended receiving ports 138, 140 including an arcuate camsurface 142 leading to an aperture 144. Inserting the ends 118 and 120of the connecting arms 96, 98 into the ports 138, 140 causes the detentprojection 122 to be depressed against the cam surface 142 until itremedies alignment with the aperture 144. At this point, the projection122 swaps into the aperture 144 so that the connecting arms 96, 98 arereleasably and rigidly connected to spreading tool actuator arms 130,132.

During the narrow blade 16, 18 retraction procedure, the shorterconnecting arm 96 is mounted to the frame 12 by the peg 112 and hole114. The arm 96 undergoes no movement with respect to the frame 12.Accordingly, squeezing the handles of the tool together only causes thelong connecting arm 98 attached to the slider pin 116 to shift relativeto the retractor frame which, in turn, causes the connected one of thenarrow blade sliders 40, 42, to shift in the longitudinal retractiondirection. During the wide blade retraction operation, which uses twolonger connecting arms 98, both of the connecting arms undergo movementwith respect to the frame 12.

After the second retraction operation, the sliders to which theinstrument 100 has been attached self-lock into position so that theinstrument 100 can be removed form the access retractor 10 withoutcausing the retractor sliders or blades to move. The slider 66, 68,shown in FIG. 13, is depicted locked in the retracted position.

A spring plunger mechanism 146 located at the end of the sliders 40, 42,66, 68 prevents unintentional back-out of the blades 16, 18, 20, and 22.The mechanism 146 includes a coil spring 148 attached to a locking pin150. The pin 150 is biased outward toward the blade 16, 18, 20, and 22.The plunger 146 locks the blades into position on the dovetail joints bypushing the locking pin 150 into the blade aperture 152. FIG. 13 showsthe spring plunger mechanism 146 without a blade attached, while FIG. 12illustrates the wide blade 20, 22 attached to the slider 66, 68. Toremove the blades from the dovetail joints 58, 60, an unlockinginstrument (not shown) is pushed into a blade aperture 152, as seen inFIG. 1. This disengages the spring plunger mechanism 146 and allows theblades to be removed from the sliders.

The spring plungers mechanism 146 is shown in FIG. 14 at the end of theslider 40, 42. As previously discussed, the spring plunger mechanism 146secures the blades 16, 18 to the sliders 40, 42. FIG. 14 alsoillustrates the ratcheting mechanism 156 of narrow blade slides 40, 42.The ratcheting slider 40, 42 has teeth 158 that cooperates with a pawlmechanism 160. The pawl mechanism 160 is attached to a leaf spring 162that is attached to the frame 12 by a screw 164. The pawl 160 is pushedtoward the teeth 158 by the leaf spring 162. The ratcheting slider 40,42 can be moved to the retracted position freely, but to move the narrowblades 16, 18 to the unretracted position, a hook 166 of the leaf spring162 must be pulled to disengage the pawl 160 from the ratcheting teeth158.

To steady the access retractor during use, the frame 12 is provided withmounting members 168. The members 168 are located opposite one anotheron the outside of the frame. These members 168 can be used to attach theretractor 10 to the patient's bed during the surgical procedure such asby using “an iron intern”, an example of which is discussed in U.S. Pat.No. 6,302,843, the disclosure of which is hereby incorporated byreference in its entirety.

Turning now to a second embodiment, the access retractor 200 of FIGS.15-32 is similar to the access retractor 10 of FIGS. 1-7 and 12-14, inthat it comprises a generally planar body or frame 202 having a central,oblong or ovular opening 204. Opposing sliders 238, 240 and 242, 244that slide in through slots 208 and 210 formed in both a longitudinaldirection and a transverse direction. A first set of tissue engagingmembers, in this example comprising narrow blades 216 and 218, arereleasably connected to associated sliders 238 and 240, as illustratedin FIGS. 15-17, 19 and 20. A second set of tissue engaging members, inthis example comprising wide blades 220 and 222, are releasablyconnected to associated sliders 242 and 244, as illustrated in FIGS. 19and 20.

One difference between the first embodiment of the access retractor 10and the second embodiment of the access retractor 200 is that the latteruses a ratchet mechanism associated with each of the sliders 238, 240,242 and 244 in order to permit movement of the sliders 238, 240, 242 and244 toward their retracted positions while restricting movement towardtheir extended positions. Another difference between the firstembodiment of the access retractor 10 and the second embodiment of theaccess retractor 200 is that the latter can be used with a spreadinginstrument in direct contact with the blades 216, 218, 220 and 222 inorder to manipulate the sliders 238, 240, 242 and 244 (and attachedblades 216, 218, 220 and 222) between their extended and retractedpositions relative to the opening 204 of the frame 202. Thesedifferences, and others, will be discussed in greater detail herein.

The frame 202 of the second embodiment of the access retractor 200 issimilar in shape to the frame or body 12 of the first embodiment of theaccess retractor 10, being generally planer and having a centrallydisposed, oblong or ovular retention opening 204 surrounded by an innerwall 206. Also similar to the access retractor 10 of the firstembodiment, the frame 202 of the access retractor 200 of the secondembodiment includes two pairs of opposing through slots 208 and 210,including a pair of transverse through slots 208 and a pair of opposinglongitudinal through slots 210. The transverse through slots 208 arealigned with the transverse or minor axis of the frame 202, and thelongitudinal through slots 210 are aligned with the longitudinal ormajor axis of the frame 202. A pair of opposing rods 212 extend from theframe 202 to permit attachment of the access retractor 200 relative to astationary frame or table using intermediate arms, such as the “ironintern.”

Sliders 238, 240, 242 and 244 are positioned in the slots 208 and 210 ofthe frame 202. The sliders 238, 240, 242 and 244 each have a dovetailconnection 254, 256, 258 and 260, respectively, to an associated blade216, 218, 220 and 222. The dovetail connections 254, 256, 258 and 260are configured to both permit releasable attachment of the blades 216,218, 220 and 222 to an associated one of the sliders 238, 240, 242 and244 and to position the attached blades 216, 218, 220 and 222 in theopening 204 of the frame 202, as in the first embodiment. A releasableconnection or locking mechanism 310, similar to the releasableconnection 90 discussed above, is provided for each slider 238, 240, 242and 244 to permit locking of an associated one of the blades 216, 218,220 and 222, and will be discussed in greater detail below.

As with the first embodiment, the releasable dovetail connections 254,256, 258 and 260 and releasable connections 310 permit pairs of theblades 216, 218 and 220, 222 to be attached to the associated sliders238, 240 and 242, 244 in a sequential manner to enable multi-stagestretching of the incision while minimizing gaps between adjacent onesof the blades 216, 218, 220 and 222 when each are in a retracted stageto reduce the encroachment of retracted tissue surrounding the incisionbetween adjacent ones of the blades 216, 218, 220 and 222 and into thesurgical site during surgical procedures. More specifically, the narrowblades 216 and 218 can be inserted into an incision, and in particularan incision that has been dilated to a size sufficient to accommodatethe width of the narrow blades 216 and 218, and then attached to theassociated sliders 238 and 240 using the dovetail connections 254 and256 and releasable connections 310 to secure the blades 216 and 218 inan extended or initial stage. The sliders 238 and 240 can then beretracted to use the attached narrow blades 216 and 218 to enlarge theincision to an intermediate stage. Once the incision is enlarged in theintermediate stage, the wide blades 220 and 222 can be inserted into theenlarged opening and attached to the associated sliders 242 and 244 intheir extended positions. Finally, the sliders 242 and 244 can be movedtoward their retracted positions to use the attached wide blades 220 and222 to further enlarge the incision in a final stage. The result, as inthe first embodiment, is an oblong-shaped opening bounded by closelyadjacent blades 216, 218, 220 and 222.

Also as in the first embodiment, a spreading instrument may be used toprovide a mechanical advantage to assist in moving the blades 216, 218,220 and 222 toward their retracted positions and thereby stretch theincision. Although the retraction tool 100 and connection arms 96 and 98can be used, as in the first embodiment, a lamina spreader 400, such asillustrated in FIG. 33, can be used instead. To use the lamina spreader,each operating end 402 and 404 of the lamina spreader 400 can be placedin abutment with the inward facing surfaces of an opposing pair ofblades 216, 218 and 220, 222. The handles 406 and 408 of the laminaspreader 400 can then be manipulated to force the abutted opposing pairof blades 216, 218 and 220, 222 in opposing directions and toward theirretracted positions. Ratchet mechanisms associated with each of thesliders 238, 240, 242 and 244 permit incremental retraction of theattached blades 216, 218, 220 and 222 while resisting the pulling forceof the surrounding tissue to urge the blades 216, 218, 220 and 222 backtoward their extended positions. The lamina spreader 400 may be of thetype sold by Life Instrument Corporation, Braintree, Mass., as modelnumber 741-1106-1, with the modifications being disablement of theratchet mechanism and removal of the teeth on the operating ends 402 and404.

The sliders 238, 240, 242 and 244 are each generally identical inconstruction, with the exception of their lengths, the number of ratchetteeth 308 and the radius of the arc 330 or 332 on the end disposed inthe opening 204, as will be discussed in greater detail below. Each ofthe sliders 238, 240, 242 and 244 includes, with reference to narrowblade slider 238 of FIGS. 21-23 and the wide blade slider 242 of FIGS.24-26, a generally flat shank 306 having an upstanding dovetailprojection 264 at one end. A plurality of ratchet teeth 308 are disposedalong a longitudinal axis of the shank 306 for engagement with a plunger290 of the plunger assembly 270 to restrict movement of the slider 238toward the extended position but not toward the retracted position. Thedovetail projection 264 is dimensioned to mate with a correspondingdovetail recess 262 formed on each of the blades 216, 218, 220 and 222.In order to provide clearance for the dovetail connections 254, 256, 258and 260, and in particular the dovetail projections 264, arcuaterecesses 326 are formed in the inner wall 206 of the frame 202 and arealigned with the sliders 238, 240, 242 and 244, as illustrated in FIGS.15-17, 19 and 20. An additional arcuate recess 328 is also provided inthe inner wall 206 of the frame 202 for each of the narrow blade sliders238 and 240 in their retracted positions.

The end of the shank 306 adjacent the dovetail projection 264 includesone of two arcs 330 or 332 facing inward toward the opening 204 of theframe 202. Each of the arcs 330 and 332 has a different radius. Inparticular, the wide blade sliders 242 and 244 each have the arc 332with the greater radius, and the narrow blade sliders 238 and 240 eachhave the arc 330 with the lesser radius. The different radii of the arcs330 and 332 have two different functions.

First, the arcs 330 and 332 function to ensure that only the wide blades220 and 222 are attached to the wide blade sliders 242 and 244 and thatonly the narrow blades 216 and 218 are attached to the narrow bladesliders 238 and 240. More specifically, each of the arcs 330 and 332 hasa radius that corresponds to a radius 233 on the narrow blades 216 and218 and a radius 234 on the wide blades 220 and 222, respectively, in aregion adjacent the dovetail recess 262. This is to ensure that only thewide blades 220 and 222 are attached to the wide blade sliders 242 and244 and that only the narrow blades 216 and 218 are attached to thenarrow blade sliders 238 and 240. The difference in the radii of the arc330 of the narrow blade sliders 238 and 240 and the region adjacent thedovetail recess 262 on the wide blades 220 and 222 prevents the wideblades 220 and 222 from being attached to the narrow blade sliders 238and 240. Likewise, the difference in the radii of the arc 332 of thewide blade sliders 242 and 244 and the region adjacent the dovetailrecess 262 on the narrow blades 216 and 218 prevents the narrow blades216 and 218 from being attached to the wide blade sliders 242 and 244.In this manner, proper attachment of the respective ones of the narrowblades 216 and 218 and wide blades 220 and 222 with the associatedslider 238, 240, 242 and 244 is assured.

Second, the arcs 330 and 332 function to provide a flush surface withadjacent portions of the inner wall 206 of the frame 202 surrounding theopening 204 in order to restrict intrusion of unnecessary componentsinto the opening 204 when the sliders 238, 240, 242 and 244 are fullyretracted. The arc 330 having the lesser radius, on the narrow bladesliders 238 and 240, is able to be flush with the adjacent portion ofthe inner wall 206 of the frame 202 when the sliders 238 and 240 arefully retracted due to a corresponding arcuate surface formed on theadjacent portion of the inner wall 206, as illustrated in FIG. 20.Similarly, the arc 332 having the greater radius, on the wide bladesliders 242 and 244, is able to be flush with the adjacent portion ofthe inner wall 206 of the frame 202 when the sliders 242 and 244 arefully retracted due to a corresponding arcuate surface formed on theadjacent portion of the inner wall 206, as also illustrated in FIG. 20.

The sliders 238 and 240 extending in the longitudinal direction of theframe 202, and associated with the narrow blades 216 and 218, havelengths greater than the lengths of the sliders 242 and 244 extending inthe transverse direction of the frame 202, and associated with the wideblades 220 and 222. The difference in lengths of the narrow bladesliders 238 and 240 compared to the wide blade sliders 242 and 244 is topermit all the blades 216, 218, 220 and 222 to be positionable in acenter region of the opening 204 of the frame 202 when the sliders 238,240, 242 and 244 are in the fully extended positions. To accommodate thedifferent in length of the major axis as compared to the minor axis ofthe oblong or ovular shaped opening 204 of the frame 202, the narrowblade sliders 238 and 240 are longer than the wide blade sliders 242 and244. Because the longer narrow blade sliders 238 and 240 have a greaterdistance of travel to go from the fully extended to fully retractedpositions as compared to the shorter wide blade sliders 242 and 244, thenarrow blade sliders 238 and 240 have a greater number of ratchet teeth308 than the wide blade sliders 242 and 244, and thus more discretepositions.

The blades 216, 218, 220 and 222 are similar in construction to eachother, with the primary exceptions of the differences in width betweenthe narrow blades 216, 218, illustrated in FIGS. 27-29, and the wideblades 220, 222, illustrated in FIGS. 30-32, and the different arcs 330and 332. The upper end of the blades 216, 218, 220 and 222 each includea dovetail recess 262 for mating with the dovetail projection 264 of theassociated slider 238, 240, 242 and 244. An opposite end of the blades216, 218, 220 and 222 includes a lip 230, which in use faces outwardfrom the opening 204 of the frame 202 to assist in maintaining theadjacent tissue from slipping under the blades 216, 218, 220 and 222.The opposite end of the blades 216, 218, 220 and 222 also includes aninclined ramp 250 to facilitate insertion of the blades 216, 218, 220and 222 into the surgical opening in a manner that urges the tissueoutwardly relative to the opening 204 of the frame 202. Positionedimmediately adjacent the lip 230 and opposite the inclined ramp 250 isan inwardly inclined surface 248, which in use is configured to directadjacent tissue surrounding the surgical opening into the crook of thelip 230. The blades 216, 218, 220 and 222 are similar in size to thoseof the first embodiment.

A plurality of through apertures 228 are formed through the blades 216,218, 220 and 222 and are aligned with the dovetail recesses 262. Theapertures 228 are configured to receive a locking pin 318 of the lockingmechanism 310 of the sliders 238, 240, 242 and 244, as illustrated inFIG. 17. The locking pin 318 is partially received in a blind bore 314of each of the sliders 238, 240, 242 and 244, and is biased outwardlytherefrom by a compression spring 312 received in a bore 316 of thelocking pin 318. The protruding tip of the pin 318 opposite its bore 316is rounded and has a diameter sized to be received in the throughapertures 228 of the blades 216, 218, 220 and 222 to restrict separationof the dovetail connections 254, 256, 258 and 260. To facilitateattachment of the blades 216, 218, 220 and 222 to their associatedsliders 238, 240, 242 and 244, ramps 252 are formed adjacent the throughapertures 228 to facilitate retraction of the locking pin 318 into theblind bore 314, and against the biasing force of the spring 312, untilthe locking pin 318 is aligned with one the through apertures 228, atwhich point the spring 312 will bias the top of the pin 318 into thethrough aperture 228 to restrict separation of the dovetail connection254, 256, 258 and 260. The locking mechanism 310 can be released in thesame manner discussed above with respect to the first embodiment. Aplurality of longitudinally-aligned through apertures 228 are providedto permit the blades 216, 218, 220 and 222 to be positioned at differentdepths relative to the frame 202.

Turning now to more of the details of the plunger assembly 270, theplunger assembly 270 includes a sleeve 274 having a radially extendingflange 282, a cylindrical upper portion 278 and an intermediatepolygonal portion 280, as illustrated in FIG. 18. The sleeve 274 alongwith the components depicted below the sleeve 274 in FIG. 18 have beenrotated 90 degrees in relation to where they would otherwise be locatedto more fully show component features. A circular opening 322 extendspartially through the frame 202 from the bottom thereof, as illustratedin FIG. 17, but stops at a distance between the slot 210 and the top ofthe frame 202. The circular opening 322 is sized to permit the radiallyextending flange 282 to fit therethrough. A polygonal opening 320extends from the top of the frame 202 and intersects the circularopening 322, and corresponds in size to the polygonal portion 280 of thesleeve 274. The polygonal opening 320 is smaller than the circularopening 322 such that an interior ledge 324 is formed at theintersection of the polygonal opening 320 and the circular opening 322.The sleeve 274 is inserted into the circular opening 322 from the bottomof the frame 202. The intermediate polygonal portion 280 of the sleeve274 mates with the corresponding polygonal opening 320 of the frame 202in order to prevent rotation of the sleeve 274 relative to the frame202.

The radially extending flange 282 engages the interior ledge 324 tolimit extension of the sleeve 274 though the polygonal opening 320 in adirection extending outward from the frame 202 while permitting thecylindrical upper portion 278 of the sleeve 274 to protrude outwardlyfrom the frame 202. A collar 272 is used to restrict movement of thesleeve 274 in a direction extending inward toward the frame 202. Morespecifically, the cylindrical upper portion 278 of the sleeve 274 hasexternal threading that mates with internal threading of the collar 272.When the collar 272 is threadingly engaged with the cylindrical upperportion 278 of the sleeve 274, the sleeve 274 is held in position on theframe 202 by the collar 272, on the outer side of the frame 202, and theengagement between the flange 282 and the interior ledge 324 on theinterior of the frame 202, while the polygonal portion 280 of the sleeve274 and the corresponding polygonal opening 320 of the frame 202 preventrotation of the sleeve 274.

A central bore 276 extends through the sleeve 274, and has a portionwith a first diameter adjacent the upper end of the bore 276 and aportion with a second, larger diameter in the remainder of the sleeve274. A plunger 290 is positioned within the central bore 276. Theplunger 290 includes a shaft 295 with a diameter sized to fit throughthe portion of the central bore 276 of the sleeve 274 having the firstdiameter. The plunger 290 also includes an enlarged head 294 having adiameter greater than the portion of the central bore 276 having thefirst diameter of the sleeve 274 such that the shaft 295 but not thehead 294 of the plunger 290 can protrude through the portion of thecentral bore 276 having the first diameter in order to retain theplunger 290 in the sleeve 274, as illustrated in FIG. 17.

A compression spring 288 is disposed in portion of the central bore 276of the sleeve having the second, larger diameter. The spring 288surrounds the shaft 295 of the plunger 290. One end of the spring isseated on a ledge 292 at the intersection of the shaft 295 and head 294of the plunger 290, while the other end of the spring is seated at aledge formed at the intersection of the first and second diameterportions of the central bore 276 of the sleeve 274. In this manner, thespring 288 biases the plunger 290, and in particular the head 294 of theplunger 290, relative to the sleeve 274 and inward into the circularopening 322 of the frame 202.

An end of the shaft 295 of the plunger 290, opposite the end having thehead 294, protrudes through the portion of the central bore 276 of thesleeve 274 having the first diameter. The protruding end of the shaft295 has a blind bore 298 with internal threading. A disc handle 300 isattached to the shaft 295 of the plunger 290 using a screw 304. Thescrew 304 extends through a bore 302 of the disc handle 300 and hasexternal threading for mating with the internal threading of the blindbore 298 of the upper end of the shaft 295 of the plunger 290. The dischandle 300 can be grasped to pull the plunger 290, and in particular thehead 294, outward relative to the circular opening 322 of the frame 202.The shaft 295 of the plunger 290 may optionally be shorted from thatillustrated, along with the axial length of the sleeve 274, in order toform a lower profile access retractor.

The head 294 of the plunger 290 has an inclined ramp surface that isconfigured to engage the ratchet teeth 308 of the associated slider 238,240, 242 or 244, as illustrated in FIG. 17. The ratchet teeth 308include inclined surfaces corresponding to the inclined ramp surface ofthe head 294 of the plunger 290. The inclined surface of each of theratchet teeth 308 is orientated such that the slider 238, 240, 242 or244 is permitted to retract, but is blocked by the plunger 290 frommoving inward relative to the opening 204 of the frame 202 unless theplunger 290 is shifted to its unengaged position using the disc handle300.

More specifically, a ledge of each of the ratchet teeth 308 ispositioned to abut against the head 294 of the plunger 290 when the head294 of the plunger 290 is biased by the spring 288 against the slider238, 240, 242 or 244. The engagement between the ledge of the ratchetteeth 308 and the head of the plunger 294 restricts the slider frommoving inward relative to the opening 204 of the frame 202 and towardthe extended position. However, the engagement between the inclined rampsurface of the head 294 of the plunger 290 and the inclined surface ofthe ratchet teeth 308 function to shift the plunger 290 to its unlockedposition, against the biasing force of the spring 288, when the slider238, 240, 242 or 244 is moved toward its retracted position. As theslider 238, 240, 242 or 244 is moved toward its retracted position, theengagement between the inclined ramp surface of the head 294 of theplunger 290 and the inclined surface of the ratchet teeth 308 cycles theplunger 290 between its locked and unlocked positions as it passes eachratchet tooth 308, thereby providing a plurality of discrete positionsof the slider 238, 240, 242 or 244 where movement toward the extendedposition, and inward relative to the opening 204 of the frame 202, isrestricted.

A pin 286 is used to restrict rotation of the plunger 290 in the sleeve274, and to maintain the inclined ramp surface of the head 294 of theplunger 290 in proper alignment with the inclined surfaces of theratchet teeth 308 of the associated sliders 238, 240, 242 and 244. Thepin 286 is positioned in an aperture 284 extending transversely throughthe sleeve 274. The aperture 284 intersects the central bore 276 of thesleeve 274, such that an intermediate portion of the pin 286 is disposedin the central bore 276. The intermediate portion of the pin 286 abuts aflat 296 formed on the shaft 295 of the plunger 290 to restrict rotationof the plunger 290 relative to the sleeve 274, and thereby to maintainthe inclined ramp surface of the head 294 of the plunger in theorientation corresponding to the orientation of the inclined surfaces ofthe ratchet teeth 308 of the associated slider 238, 240, 242 or 244.

The frame 202 may be formed from a carbon-fiber material, and inparticular from a carbon-filled PEEK. The sliders 238, 240, 242 and 244and blades 216, 218, 220 and 222 may be formed from anodized titaniumnitrate. Preferably, all of the components of the access retractor 200can be readily disassembled and are suitable for sterilization, such asin an autoclave.

While there have herein been illustrated and described with respect tospecific examples and embodiments, including presently preferred modesof carrying out the invention, those skilled in the art will appreciatethat there are numerous variations and permutations of theabove-described apparatus and methods that fall within the scope andspirit of the invention as set forth in the appended claims.

1. An access retractor for enlarging an incision in a retractionprocedure, the retractor comprising: a first set of opposing tissueengaging members that retract in outwardly opposing directions along afirst axis; a second set of opposing tissue engaging members thatretract in outwardly opposite directions along a second axis transverseto the first axis; a predetermined width of each of the second set oftissue engaging members that is greater than a predetermined width ofeach of the first set of tissue engaging members so that the first setof tissue engaging members are narrow tissue engaging members and thesecond set of tissue engaging members are wide tissue engaging members;operating mechanisms of the first and second set of tissue engagingmembers that allow for the first set of narrow tissue engaging membersto be retracted in an initial stage of the retraction procedure and thesecond set of wide tissue engaging members to be retracted in asubsequent stage of the retraction procedure; slider members of theoperating mechanisms associated with the first narrow set of tissueengaging members; a slide connection between each of the slider membersand the first narrow set of tissue engaging members to allow the narrowtissue engaging members to slide onto the slider members, the slideconnections being configured to fix the narrow tissue engaging membersagainst rotation relative to the associated slider member and maintainthe narrow tissue engaging members in a generally parallel orientationto one another while the narrow tissue engaging members are connected tothe slider members; a slide connection between the wide tissue engagingmembers and the associated operating mechanisms configured to allow thewide tissue engaging members to be slid on and off of the associatedoperating mechanisms so that the wide tissue engaging members can beslid onto the associated operating mechanisms after the narrow tissueengaging members have retracted in the initial stage of the retractionprocedure; and locking mechanisms for selectively locking the widetissue engaging members relative to the associated operating mechanisms.2. The access retractor of claim 1, wherein the operating mechanisms aremounted relative to a frame to position at least a portion of the firstand second sets of tissue engaging members in a retention opening of theframe, and the tissue engaging members of the first and second sets havereleasable connections to the operating mechanisms.
 3. The accessretractor of claim 2, wherein at least the operating mechanisms of thefirst set of tissue engaging members each include a self-locking devicepermitting locking of the first set of tissue engaging members relativeto the second set of tissue engaging members.
 4. The access retractor ofclaim 3, wherein the self-locking devices permit movement of the firstset of tissue engaging members in outwardly opposite directions alongthe first axis but selectively restrict movement of the first set oftissue engaging members toward each other.
 5. The access retractor ofclaim 4, wherein the self-locking devices comprise a ratchet mechanism.6. The access retractor of claim 5, wherein the ratchet mechanismcomprises: a plurality of ratchet teeth formed on the slider members ofthe operating mechanisms of the first set of tissue engaging members,the slider members slidable in slots of the frame; bores of the framenormal to and intersecting the slots; a sleeve mounted to the frame, thesleeve having an upper bore of a first diameter and a lower boreadjacent the frame of a second diameter, the first diameter being lessthan the second diameter and the bores of the sleeve being coaxial withthe bore of the frame; a plunger translatable between a locked positionwhere the plunger extends through the bore of the frame into engagementwith one of the ratchet teeth of the slider member to retain the slidermember relative to the frame and an unlocked position where the plungeris unengaged with the one of the ratchet teeth of the slider member topermit the slider member to translate relative to the frame; and aspring disposed in the lower bore of the sleeve biasing the plungertoward the locked position.
 7. The access retractor of claim 6, wherein:a flat is disposed on the plunger; a transverse aperture extends throughthe sleeve and intersects the lower bore of the sleeve; and a pin isdisposed in the transverse aperture and engages the flat on the plungerto restrict the plunger from rotating in the sleeve.
 8. The accessretractor of claim 2, wherein the slide connection between each of thewide tissue engaging members and the associated operating mechanismscomprises dovetail recesses formed in one of the tissue engaging membersand the operating mechanisms that mates with a dovetail projectionformed in the other of the tissue engaging members and the operatingmechanisms.
 9. The access retractor of claim 2, wherein the retentionopening is non-circular.
 10. The access retractor of claim 2, wherein atleast one of the tissue engaging members is inclined relative to adirection normal to a plane of the frame.
 11. An access retractor forenlarging an incision in a retraction procedure, the retractorcomprising: a frame; a narrow set of opposing tissue engaging members;operating mechanisms of the narrow set of tissue engaging membersconnected to the frame and operable to retract the narrow set of tissueengaging members to enlarge the incision to an intermediate sizeopening; slider members of the operating mechanisms associated with thenarrow set of tissue engaging members; a wide set of opposing tissueengaging members for being inserted into the intermediate size opening;operating mechanisms of the wide set of tissue engaging membersconnected to the frame and operable to retract the wide set of tissueengaging members to enlarge the intermediate size opening to an enlargedopening with gaps between adjacent tissue engaging members kept to aminimum; a dovetail slide connection between each of the slider membersand the narrow set of tissue engaging members to allow the narrow tissueengaging members to slide onto the slider members, the dovetail slideconnections being configured to fix the narrow tissue engaging membersagainst rotation relative to the associated slider member and maintainthe narrow tissue engaging members in a generally parallel orientationto one another while the narrow tissue engaging members are connected tothe slider members; a plurality of predetermined, vertically spacedpositions between at least one operating mechanism and an associatedtissue engaging member at which the associated tissue engaging membercan be fixed relative to the at least one operating mechanism to allowthe associated tissue engaging member to be selectively slid todifferent depths relative to the frame; and a locking mechanism forreleasably fixing the associated tissue engaging member relative to theat least one operating mechanism at one of the plurality of verticalspaced positions.
 12. The access retractor of claim 11, wherein theoperating mechanisms are mounted relative to the frame to position atleast a portion of the narrow and wide tissue engaging members in aretention opening of the frame.
 13. The access retractor of claim 12,wherein the retention opening is generally ovular.
 14. The accessretractor of claim 11, wherein the wide tissue engaging members havereleasable connections to the operating mechanisms.
 15. The accessretractor of claim 14, wherein the narrow tissue engaging members havereleasable connections to the operating mechanisms.
 16. The accessretractor of claim 12, wherein the operating mechanisms of the narrowset of tissue engaging members each include a self-locking devicepermitting locking of the narrow set of tissue engaging members relativeto the frame, the self-locking devices permitting retraction of thenarrow set of tissue engaging members and restricting movement of thenarrow tissue engaging members toward each other.
 17. The accessretractor of claim 11 further comprising vertical bearing surfaces ofthe dovetail slide connection which slide relative to one another andpermit the associated tissue engaging member to be slid to differentdepths relative to the frame.
 18. An access retractor for enlarging anincision during a retraction procedure, the retractor comprising: aframe configured to extend about a retention opening; a first pair oftissue engaging members operatively connected to the frame for beingdisposed in the retention opening; initial stage operating mechanismsconnected to the frame and each having one of the first pair of tissueengaging members connected thereto with the initial stage operatingmechanisms configured to retract the first pair of tissue engagingmembers in opposite directions away from each other to enlarge theincision to an intermediate size opening; initial stage slider membersof the initial stage operating mechanisms associated with the first pairof tissue engaging members; an initial stage slide connection betweeneach of the initial stage slider members and the first pair of tissueengaging members to allow the first pair of tissue engaging members toslide onto the initial stage slider members, the initial stage slideconnections being configured to fix the first pair of tissue engagingmembers against rotation relative to the associated initial stage slidermember and maintain the first pair of tissue engaging members in agenerally parallel orientation to one another while the first pair oftissue engaging members are connected to the initial stage slidermembers; a second pair of tissue engaging members that are disconnectedfrom the frame so that only the first pair of tissue engaging membersare inserted into the incision prior to operation of the initial stageoperating mechanisms to retract the first pair of tissue engagingmembers to minimize the size of the incision necessary to receive thetissue engaging members therein; subsequent stage operating mechanismsconnected to the frame and being configured to have the second pair oftissue engaging members connected thereto after the incision opening isenlarged to the intermediate size opening for extending therein;subsequent stage slider members of the subsequent stage operatingmechanisms associated with the second pair of tissue engaging members; asubsequent stage slide connection between each of the subsequent stageslider members and the second pair of tissue engaging members to allowthe second pair of tissue engaging members to slide onto the subsequentstage slider members, the subsequent stage slide connections beingconfigured to fix the second pair of tissue engaging members againstrotation relative to the associated subsequent stage slider member andmaintain the second pair of tissue engaging members in a generallyparallel orientation to one another while the second pair of tissueengaging members are connected to the subsequent stage slider members.19. The access retractor of claim 18, wherein the first pair of tissueengaging members have a predetermined width and the second pair oftissue engaging members have a predetermined width, the predeterminedwidth of the second pair of tissue engaging members being greater thanthe predetermined width of the first pair of tissue engaging members sothat the first pair of tissue engaging members are narrow tissueengaging members and the second pair of tissue engaging members are widetissue engaging members.
 20. The access retractor of claim 18 furthercomprising: an end portion of each of the subsequent stage slidermembers disposed within the retention opening; a mating portion of eachof the second pair of tissue engaging members which permits the tissueengaging member to be passed downwardly onto the end portion of anassociated subsequent stage slider member and connected thereto; and ablade portion of each of the second pair of tissue engaging memberswhich passes into the intermediate size opening as the mating portion ispassed downwardly onto the end portion of the associated subsequentstage slider member.
 21. The access retractor of claim 11, furthercomprising: vertical bearing surfaces of the at least one operatingmechanism and the associated tissue engaging member configured to sliderelative to one another, the at least one operating mechanism having abore extending in the vertical bearing surface thereof; wherein thelocking mechanism comprises a pin disposed at least partially within thebore, the pin being slidable orthogonal to the vertical bearing surfaceof the associated tissue engaging member between an extended positionwhere the pin contacts the tissue engaging member to fix the tissueengaging member relative to the one operating mechanism and a retractedposition where the pin is spaced from the tissue engaging member topermit the tissue engaging member to slide along the one operatingmechanism.